Are Chemicals Making You Fat?

Scientists differ on effect of "obesogens."

Poor eating habits and too little exercise undoubtedly have led to the nation’s struggle with weight. But some scientists believe there’s another culprit at play in the obesity epidemic: environmental chemicals that interfere with metabolism. These chemicals, called “obesogens,” may influence the metabolic process and predispose some people to weight gain regardless of calorie restriction and activity level.

Obesogens are fairly new, and controversial, and three varying perspectives on their role in weight gain are offered in the June issue of Obesity.

In the first article, the authors argue that exposure to chemicals in utero and during early childhood can lead to weight issues later in life. They cite a study that showed that exposing mice to a certain fungicide resulted in the accumulation of permanent fat tissue. They write that some obesogens, including one found in a plastic used to make food containers, affect impulse control, and that these and other obesogens appear to influence eating behaviors. The researchers propose that exposure to obesogens combined with excess food intake and low activity levels create a “perfect storm” for obesity.

The authors of the second article are skeptical. They emphasize that the studies largely involved animals, and that the high dose levels used in the research do not mimic the exposure experienced by people. They also point to the fact that the fatty foods found in the Western diet are one of the main sources of exposure to obesogens.

The third perspective says it’s too soon to draw conclusions, and the authors introduce ongoing research on the topic. OBELIX, a large European study, includes both animal studies using doses of chemicals that reflect human exposure and research that investigates the effects of exposure to obesogens before birth and during breastfeeding.